Aerodynamic Impacts of Helicopter Blade Erosion Coatings

Calvert, Mark; Wong, Tin-Chee

doi:10.2514/6.2012-2914

Cited by 8 publications

(4 citation statements)

References 3 publications

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“…This mimics the use of protective leading edge tapes or coatings used for helicopter and wind turbine blades. Protective tapes without the serration have previously been studied and shown to protect the rotor blades while significantly increasing the profile drag [22]. Qualitative investigations adding the serration suggested that it could mitigate the added drag.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a Serrated Edge to Mitigate the Adverse Effects of a Backward-Facing Step on an Airfoil

KC,

Wilson,

Alexander

et al. 2023

Inventions

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Backward-facing steps are commonly formed on wings and blades due to misalignment between segments or the addition of protective films. A backward-facing step (BFS) is known to degrade the airfoil performance. To mitigate these adverse effects, a three-dimensional low-profile serrated pattern (termed sBFS) was applied downstream of a BFS on an LA203A profile airfoil. The model drag was determined from wake surveys using a traversing Pitot-static probe within a subsonic wind tunnel operating at a chord-based Reynolds number of 300,000. The airfoil spanned the wind tunnel width (914 mm) and had a 197 mm chord length. Four different sBFS configurations were tested, each formed by applying a 1 mm thick film around the model leading edge. In addition, a BFS at various chord locations and a clean wing (i.e., no film applied) were tested for reference. The sBFS was able to reduce the drag relative the BFS by up to 8–10%, though not outperforming the clean wing configuration. In addition, the wake surveys showed the sBFS produced strong coherent structures that persist into the far-wake region (five chord length downstream of the model) with a scale that was much larger than the step height. Additionally, a computational study was carried out to further examine the flow behavior on the airfoil that produced the coherent structures. This showed that fluid near the surface gets entrained towards the sBFS downstream tip of the sBFS, which creates the initial rotation of these coherent structures that persist into the far-wake region.

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Section: Introductionmentioning

confidence: 99%

Evaluation of a Serrated Edge to Mitigate the Adverse Effects of a Backward-Facing Step on an Airfoil

KC,

Wilson,

Alexander

et al. 2023

Inventions

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“…The blades make pitch movements around the longitudinal axis, forward-backward movement within the rotational plane, and flutter up and down perpendicular to the rotational plane. Therefore, the helicopter has high maneuverability and a good control response [ 21 ]. The shaft is positioned in the upper part of the body in order that the center of gravity is in line with the vertical axis.…”

Section: The Selection and Design Of Subsystemsmentioning

confidence: 99%

Conceptual design and optimization of a sustainable and environmentally friendly archetypal helicopter within the selection criteria and limitations

Gunaltili,

Ekici,

Kalkan

et al. 2023

Heliyon

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“…The area of coatings and materials is an active research avenue in itself, and sacrificial coatings seem to be the norm. Calvert et al [3] have shown that the application of sacrificial erosion as well. This is one of the most successful models that has been used along with the Wilcox roughness model (discussed later) for turbomachinery applications.…”

Section: Introductionmentioning

confidence: 98%

Variable Surface Roughness Modeling for Skin Friction Estimation

Medida

Baeder

Nigam

et al. 2014

52nd Aerospace Sciences Meeting

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Rotor blade erosion is a common problem for DoD rotorcraft operating in harsh environments, and leads to huge replacement costs. Sacrificial coatings are often used on the blades to reduce the blade wear and tear, hence increasing its lifetime. But the uneven erorision of the coating and/or the blade creates a variable surface roughness profile which drastically affects the aerodynamic performance, and ultimately the flight envelope. Hence, it becomes crucial to be able to predict the aerodynamic forces on the blade, in particular the skin friction drag under variable roughness. In this work, we have developed portable, robust and efficient numerical techniques for turbulence and transition modeling incorporating variable roughness effects. In particular we have use a modified version of the one-equation Spalart-Allmaras (S-A) model, coupled to modified Langtry's − ̅̅̅̅̅̅ model with Boeing and ONERA roughness models. We also compare them to the two-equation Shear Stress Transport (SST) k-ω-Wilcox with Langtry's model, and experimental data from available literature. For variable roughness we investigate Dassler's additional transport equation model and present a novel technique for roughness induced transition.We draw conclusions about the pros and cons of all these techniques and outline ideas for future improvements. Effects of surface roughness and laminar-turbulent transition on the performance of a four-bladed rotor were quantified using a comprehensive analysis tool. Inclusion of surface roughness reduced the estimate of maximum rotor thrust and increased the estimate of required rotor power. Inclusion of laminar-turbulent transition decreased the estimate of required rotor power.

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Aerodynamic Impacts of Helicopter Blade Erosion Coatings

Cited by 8 publications

References 3 publications

Evaluation of a Serrated Edge to Mitigate the Adverse Effects of a Backward-Facing Step on an Airfoil

Evaluation of a Serrated Edge to Mitigate the Adverse Effects of a Backward-Facing Step on an Airfoil

Conceptual design and optimization of a sustainable and environmentally friendly archetypal helicopter within the selection criteria and limitations

Variable Surface Roughness Modeling for Skin Friction Estimation

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